On Sat, 16 Dec 2006 19:50:40 -0500, Shmuel Metz (Seymour J.) <[EMAIL PROTECTED]> wrote:
>... >>The Mod 30 had a 1401 emulator. You ran a configuration deck into >>the system and the microcode allowed the hardware to execute 1401 >>code. > >No. The Compatibility Initialization Deck (CID) was a S/360 program. >It used normal S/360 instructions along with instructions added by >the[1] emulator feature. Otherwise COS would have been impossible. >That was true for the 360/30, the 360/40 and the 360/50. >... My experience with these was as an operator so I wasn't looking under the covers. I probably missed a lot. And this was at am IBM Datacenter so The Mod 40 stuff I saw may have been something in development - something that was microcode- and model-independant. I have no wa of knowing. Given those caveats, ... I didn't mean to imply that the CID was not an S/360 program; just that it did something that enabled emulation. The CID was 2 pretty small deck - 2 or 3 inches I think. I don't think it included the emulation support. On the other hand the Mod 40 Simulator that I remember was disk-resident. I was told it used much less (if any) microcode assist. >>I don't remember what operating system) > >None, at least until COS came along; then it was DOS/360. > >>Thos 2 samples both gloss over tons of details, > >The Devil is in the details. 1401 emulation worked basically the same >on the 2030 and the 2040. > >An additional bit of confusion is caused by the fact the for the low >end S/370 systems IBM provided a program that they called a 1401/1410 >emulator that would use an installed emulator feature to speed of >simulation but that would also run on a system without the emulator >feature. It is possible that that was the "Simulator" I was refering to. At any rate, I remember the Datacenter SEs making a big deal out of the difference the 2 types of 1401 assist - that the emulator had a lot more being done at the microcode level; that the emulator was effectively executing 1404 code while the simulator was interpretting it. Pat O'Keefe ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
